Gree GRS-CQ6.0Pd/Na-K Service Manual page 84

AIR-TO-WATER HEAT PUMP
expansion vessel.
Example 2： The indoor unit is installed on the highest spot of the water system and
the total water volume is 350L.
① As the volume of water system is higher than 280L, it is necessary to adjust the
pressure of the expansion vessel be lower.
② The formula of calculating pressure
③ The maximum volume of the water system is about 410L. As the actual volume of
the water system is 350L, the expansion vessel meets the installing requirement.
④ Adjust the pre-set pressure of the expansion vessel from 1.0Bar to 0.3Bar.
Selection of expansion valve
Formula:
--- Volume of expansion vessel
v
--- Total water volume
c
--- Pre-set pressure of expansion vessel
p
1
-- The highest pressure during running of the system (that is the action
p
2
pressure of safety valve.)
--- The expansion factor of water (the difference between the expansion factor of
e
the original water temperature and that of highest water temperature.)
Temperature（℃）
10
20
30
40
45
50
55
60
65
70
75
80
85
90
95
100
=
P ( H /10 0.3) (0 /10 0.3) 0.3
g
v=
1
Water expansion factor in different temperature
0
4
+ = +
⋅
c e
+
1 p
−
1
+
1 p
2
0.00013
0.00027
0.00177
0.00435
0.00782
INSTALLATION
=
Bar
Expansion factor
e
0
0.0099
0.0121
0.0145
0.0171
0.0198
0.0227
0.0258
0.029
0.0324
0.0359
0.0396
0.0434
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